I am trying to investigate a performance issue that happened couple of weeks ago. For 20 mins, many users could not log in to a system. The application in question uses a database that has the user details, controls access based on the information on that database tables, etc.

Users reported the outage lasted from 2.42 to 2:54.

I looked at SQL logs and I can't find any thing until 2.54. I get the a stream of these at 2:54

The client was unable to reuse a session with SPID 82, which had been reset for connection pooling. The failure ID is 29. This error may have been caused by an earlier operation failing. Check the error logs for failed operations immediately before this error message.

Had you hit some worker thread maximum ? It's difficult to know unless you were monitoring.Failure ID 29 is the RedoLoginException - consider analysing memory pressureIs there anything in the Application Log?

As it's been a few weeks - even finding something in the default trace is unlikely - as the logs will have rolled over